Fertilizer and seed are what you might call the best of frenemies.
They need each other but if conditions aren’t right, one of them (in this case, the seed) is likely to get hurt.
And that goes double if you’re growing a small-seed crop like canola under dry conditions.
Three of the biggest concerns canola producers face are how much phosphate to put in the seed row, how far it should be placed from the seed, and how to get the best results from single-shoot seeding systems.
But take a “first things first” approach and start with a soil test, said Mark Cutts, an agrologist with Alberta Agriculture and Forestry.
“You have some time in the spring before seeding to collect a sample that would reflect the conditions at this point in time,” said Cutts. “That would be a good starting point for the 2019 growing season.”
How much is too much?
The Canola Council of Canada recommends placing no more than 20 pounds per acre of phosphate in the row, with all other fertilizer (including any extra required phosphate) in a side row or mid-row band where it will not hurt germinating seeds.
Of course, you’re not always going to need that much phosphate — generally, the more phosphate you can keep out of the seed row, the better, said a canola council agrologist.
“Soil that has been well manured or well fertilized over the years is probably not going to be very deficient in phosphorus,” said Greg Sekulic. “In those cases you are probably not going to see a yield response from putting that phosphate in the seed row.
“More importantly, the risk of fertilizer burn is going to overwhelm the benefit of seed row placement, in which case you would want to fertilize just for maintenance with phosphate in a side band.”
Sekulic’s rule of thumb is if you have less than five parts per million (ppm) phosphorus in the soil, go ahead and put some in the seed row. If you have 20 ppm or more, don’t. In between those two extremes, it’s your call.
Watch it when it’s dry
When it’s dry, agrologists recommend you ease back on fertilizing (especially in the seed row) to minimize seed damage — and that’s especially true for canola and other small-seed crops.
“When I refer to some of the publications out there that talk about the amount of fertilizer that you can seed place, those are based on good soil moisture conditions,” said Cutts.
“If soil moisture conditions are dry in a given year then producers may have to look at backing off the amount of fertilizer that they place.”
Seedbed utilization is another key tactic for managing canola and fertilizer under dry conditions. For most Prairie soils with adequate moisture, the standard inch and a half of separation to the side and below is acceptable, said Sekulic. But in sandy soils, move the fertilizer a bit farther away — but still close enough so the nutrients can do their job.
“By and large, the farther you can get fertilizer from the seed the safer it’s going to be, but it does come down to a balance in efficiency,” said Sekulic.
“That being said, I am definitely a fan of the mid-row band system, especially with nitrogen and sulphur in the mid-row bands. With those, there is definitely enough time for the plant roots to get over to that fertilizer without any negative impact on yield.”
Use a check strip
The effects of seed damage from fertilizer are not always immediately obvious.
Consider a case where it results in four or five days of delayed emergence, said Sekulic.
“If the entire field was that way you probably wouldn’t be able to tell except that your emergence is a little slower,” he said.
That’s why Sekulic recommends leaving a check strip somewhere in the field.
“I’m not talking about a 20-acre check strip — I’m talking about a small area where you turn the fertilizer off in the seed row for just a few metres,” he said.
“If you can find that spot when you are out scouting and see increased plant stands or better emergence in the check strip, then you know the fertilizer is negatively impacting your emerging stand. You may need to put a little more separation between the seed row and the side band or put a little less product in that seed row.”
The practices discussed above have assumed a grower’s ability to place seed and fertilizer in a single pass. However, not all producers have the equipment for that.
“There are a lot of producers who still have single-shoot systems and are still trying to fertilize for those top yields,” said Sekulic.
In those cases, he recommends a banding operation in which nitrogen, sulphur, potassium, and any remaining necessary phosphate is applied in a second pass.
“As much as I’m a zero-till zealot, from an efficiency perspective a low-disturbance fertilizer pass is probably more beneficial.”
The next best practice, he said, would be a well-timed broadcast application of nitrogen, potassium, and sulphur with as much phosphorus in the seed row as is safe.
“I want to be very clear that I would far rather see them band fertilizer than surface apply. However, there are steps you can take to increase fertilizer efficiency like treating urea, for example, with release inhibitors or coatings.”